Saturn's A-ring Soaks Up Debris Ejected from Nearby Moon

ScienceDaily is running a story about the recently discovered interaction between Saturn's A-ring and one of Saturn's small moons, Enceladus. Thanks to data from Cassini, scientists have discovered that ejected matter from Enceladus' ice geysers is absorbed into the A-ring, where it is then trapped. We discussed the geysers themselves a few years ago, and researchers have been working since then to determine where the material was going. Quoting: "This is the latest surprising phenomenon associated with the ice geysers of Enceladus to be discovered or confirmed by Cassini scientists. Earlier, the geysers were found to be responsible for the content of the E-ring. Next, the whole magnetic environment of Saturn was found to be weighed down by the material spewing from Enceladus, which becomes plasma -- a gas of electrically charged particles. Now, Cassini scientists confirm that the plasma, which creates a donut-shaped cloud around Saturn, is being snatched by Saturn's A-ring, which acts like a giant sponge where the plasma is absorbed."

Re:Moons creating moons?

[mrxak]

No doubt new comets or other objects are going by and getting ripped apart all the time to add to Saturn's rings, but Saturn has a lot of moons already, so clearly Saturn is getting moons somehow.

Re:Moons creating moons?

[Speare]

IANAAP, and I'm not disagreeing with the basic point of what you are saying, but...

from the link you provided, the radius of the Roche limit (1) depends on the structural integrity of the satellite, not just a constant radius from the stronger body, and thus (2) does not apply at all to the pulverized bits of the weaker body.

The Saturn A ring therefore decorates a particular Roche limit that applied to some other body that was pulverized in the past, and not a guaranteed "point of no moons" around Saturn. If the Roche limit were not based on the structural integrity of the moon, then even the broken boulders of an ex-moon would be further pulverized into rocks, then sand, and finally nano-dust. If a boulder survives inside the original body's Roche limit, it must be because it has a new Roche limit that is closer to Saturn.

While I admit that the pulverized bits are unlikely to coalesce into a moon, I wouldn't say they're impossible. If something were to cause a strong self-attractive force, say, some ionizing comet or who knows, the FSM's noodly appendages, a moon that developed into a highly rigid structure could continue to survive there. If we someday mine asteroids in the region, structural integrity of manmade or man-inhabited objects will obviously be of prime importance.